1. Field of the Invention
The present invention relates to a solid electrolytic capacitor, and more particularly to a structure of a cathode lead frame.
2. Description of the Related Art
With digitization of an electronic device, a solid electrolytic capacitor for use is required to be smaller in size and larger in capacitance, and a solid electrolytic capacitor disclosed in Japanese Unexamined Patent Publication No. 10-64761 is conventionally known.
FIG. 24 is a schematic cross-sectional view showing a structure of a conventional solid electrolytic capacitor. Referring to FIG. 24, a conventional solid electrolytic capacitor 200 comprises a capacitor element 210, an anode lead frame 220, a cathode lead frame 230, an adhesive 240 and an exterior resin 250.
The capacitor element 210 has a structure that a dielectric coating film, a solid electrolyte layer and a cathode extraction layer are sequentially formed on a surface of an anode body made of a sintered body of a valve action metal such as tantalum, niobium, titanium, aluminum and the like. The capacitor element 210 has an anode lead pin 211 integrally formed with the anode body.
The anode lead frame 220 comprises a first part 220A and a second part 220B. And the first part 220A is disposed inside the exterior resin 250 to be connected to the anode lead pin 211. The second part 220B is disposed along the exterior resin 250 at the outside of the exterior resin 250.
The cathode lead frame 230 comprises a first part 230A and a second part 230B. The first part 230A is disposed inside the exterior resin 250 to be connected to the cathode extraction layer of the capacitor element 210 by the adhesive 240. The second part 230B is disposed along the exterior resin 250 at the outside of the exterior resin 250.
The adhesive 240 is disposed between the capacitor element 210 and the first part 230A of the cathode lead frame 230. The exterior resin 250 covers the capacitor element 210, the first part 220A of the anode lead frame 220, the first part 230A of the cathode lead frame 230 and the adhesive 240.
When the capacitor element 210 is covered and sealed with the exterior resin 250, the thickness of the exterior resin 250 is set so that the first part 230A of the cathode lead frame 230 will not protrude from the exterior resin 250 due to a dimensional error and the like.
Moreover, the thicknesses of the anode lead frame 220 and the cathode lead frame 230 are set so that a problem such as deformation will not occur during delivery in a manufacturing process of the solid electrolytic capacitor 200, thereby ensuring the strength of the anode lead frame 220 and the cathode lead frame 230.